Lewis Acidic Support Boosts C-C Coupling in the Pulsed Electrochemical CO 2 Reaction.

Copper-oxide electrocatalysts have been demonstrated to effectively perform the electrochemical CO 2 reduction reaction (CO 2 RR) toward C 2+ products, yet preserving the reactive high-valent CuO x has remained elusive. Herein, we demonstrate a model system of Lewis acidic supported Cu electrocatalyst with a pulsed electroreduction method to achieve enhanced performance for C 2+ products, in which an optimized electrocatalyst could reach ∼76% Faradaic efficiency for C 2+ products (FE C 2+ ) at ∼-0.99 V versus reversible hydrogen electrode, and the corresponding mass activity can be enhanced by ∼2 times as compared to that of conventional CuO x . In situ time-resolved X-ray absorption spectroscopy investigating the dynamic chemical/physical nature of Cu during CO 2 RR discloses that an activation process induced by the KOH electrolyte during pulsed electroreduction greatly enriched the Cu δ+ O/Zn δ+ O interfaces, which further reveals that the presence of Zn δ+ O species under the cathodic potential could effectively serve as a Lewis acidic support for preserving the Cu δ+ O species to facilitate the formation of C 2+ products, and the catalyst structure-property relationship of Cu δ+ O/Zn δ+ O interfaces can be evidently realized. More importantly, we find a universality of stabilizing Cu δ+ O species for various metal oxide supports and to provide a general concept of appropriate electrocatalyst-Lewis acidic support interaction for promoting C 2+ products.